This invention concerns apparatus and methods for forming portions of foodstuffs, particularly frozen foodstuffs.
It is known to reshape presized portions of frozen food products in two or three dimensions so as to form an attractive looking shape for the final foodstuff presented to the customer. Such processes have been applied to frozen fish and poultry and can be applied to other foodstuffs as well.
For a general discussion of the background to the invention, see UK Application No. 9316721.1 (2,280,869).
The consumer market to which these processed food portions are supplied, requires the portions to possess a natural appearance, as well as texture and xe2x80x9cbitexe2x80x9d characteristic of the natural foodstuff.
In practice, it has proved to be quite difficult to reproduce the external appearance of the natural foodstuff, and simultaneously preserve the characteristic texture and xe2x80x9cbitexe2x80x9d.
In particular a fish fillet will generally contain much detailed topography and possess a relatively complex shape. Theoretically the overall shape can be reproduced by placing a small frozen block of fish (known as a charge-piece) into a die-set and applying sufficient pressure to force it into the required overall shape to form in the surface the topography characteristic of a fish fillet. The problem arises however that the high pressure required to achieve reshaping as well as the surface topography, and the relatively large and rapid movement of the frozen product needed to achieve this, can cause a great deal of crush in the charge material, and this results in an unacceptable loss of texture and xe2x80x9cbitexe2x80x9d in the final product portion.
Ideally the frozen charge-piece should be subject to minimal stress throughout the shaping process in order to retain the desired texture and xe2x80x9cbitexe2x80x9d.
To this end, it has been common to leave foodstuffs in the form produced by the cutting and sawing (ie generally rectilinear) and the final shaped portions have tended to look like short planks or blocks, rather than resemble a natural looking fish fillet, and have merely been coated with breadcrumbs or batter.
It is an object of the present invention to improve the shaping and surface topography of a reshaped frozen portion, whilst retaining bite and texture of the natural foodstuff.
Surprisingly it has been found that if a controlled volume of liquid water is included in the shaping process applied to the surface of the frozen foodstuff, higher pressures can typically be exerted so as to achieve the shaping and surface finish desired without significant loss of texture and therefore xe2x80x9cbitexe2x80x9d in the foodstuff.
This can be achieved by spraying a water-mist onto the die-set and/or onto the frozen charge-piece immediately before pressing. The presence of the water has the effect of lubricating the points of contact between the die-set and the frozen charge-piece, and a flow of product within the die-set seems to occur as the die-set is closed on the charge-piece and pressure is applied.
It has been found that the wetted surface regions of frozen charge-piece material can be made to xe2x80x9cflowxe2x80x9d over steep peaks and valleys and around complex shapes within the die-set, with less pressure on, and therefore crush of, the frozen product.
As a result of this the final portion can be made to look natural both in shape and surface while retaining the original texture and xe2x80x9cbitexe2x80x9d characteristic of the foodstuff.
Since a good replication of the surface topography characteristic of the foodstuff can thereby be obtained, the final formed product can be presented for sale and consumption without a bread-crumb or batter coating, which has tended to be added to such product in the past so as to disguise the surface finish and/or shape of the foodstuff below.
By using multiple similar pockets in a single die set, so multiples of the final portion shape can be produced from the one die-set, thereby increasing productivity.
According therefore to one aspect of the present invention in a method of forming consumer portions from a block of frozen foodstuff wherein similarly sized sections of the frozen block are removed by severing and shaped into differently shaped consumer portions under pressure between tooling of a forming press, and in which each section is of a similar size and volume so that when the press is operated the severed section is formed into a consumer portion of known volume and wherein each said consumer portion is ejected for further processing after the tooling separates, the improvement comprising the step of wetting the surface of each of the severed sections of foodstuff with a liquid just before the pressing operation, thereby to assist in shaping the sections within the forming press, and in particular to improve the formation of surface features in the consumer portion corresponding to indentations and ridges in the surface of the tooling.
In the aforementioned method the wetting of each severed foodstuff section may occur as it advances towards or as it enters the press tooling or after the severed foodstuff section has entered the tooling. In this last event the liquid used for wetting may be incident on the foodstuff or the tooling or both.
Thus for example the wetting of the foodstuff sections may be achieved by wetting the inside surface of the tooling and transferring the liquid to the foodstuff surface as the tooling comes into contact therewith.
The method may also comprise severing elongate lengths of foodstuff from a frozen block to form so-called planks, individually advancing each plank into a severing and forming press so that the leading end of the plank is appropriately positioned between upper and lower parts of the tooling, operating the latter so as to sever the leading end from the remainder of the plank and under pressure forming the severed end into the differently shaped frozen consumer portion which is removed for further processing after the tooling separates.
Alternatively the final severing step may be separated from the forming tool so that the latter only has to compress the severed section of frozen foodstuff and does not have to sever it from the remainder of a larger piece or plank of the material.
In a method in which the leading end of the plank is severed by the tooling, the advancement of the foodstuff between the tooling is achieved by advancing the plank incrementally so as to present the leading end of the plank between the severing and forming tooling as required.
Where the severing step is separate from the forming step, the frozen material is severed into individual identical sections which are then transported individually into the forming press tooling.
According to another aspect of the present invention, apparatus adapted to perform the method of the invention comprises severing means for severing sections from the block of foodstuff, forming apparatus comprising upper and lower tooling which is adapted to receive a severed section of frozen foodstuff therebetween and is further adapted to close thereon to compress the severed section into a desired shape determined by the internal topography and dimensions of the tooling, means for expelling the formed product after the tooling separates, a supply of liquid, typically water, under pressure, valve means controlling the flow of the liquid through discharge means, thereby to wet each severed foodstuff section before it is subjected to shaping by the tooling.
In one embodiment the upper and lower tooling is adapted to sever a section of frozen foodstuff material from an elongate length of the material which has been advanced between the tooling and thereafter to shape the severed leading end of the material into the desired shape.
In another embodiment all of the severing of the sections of frozen material from the block is performed upstream of the press and conveying means is provided for presenting the similar severed foodstuff sections to the tooling, one by one, and the tooling is only required to compress and shape the sections of frozen foodstuff presented thereto.
Where planks of frozen foodstuff are generated by the severing of a rectilinear block of frozen material, the ends of the planks may be wetted and freeze welded end to end so as to form a continuous length of material to be presented to a final severing step to form sections for supply to the pressing operation, so that if the plank-lengths do not equate to a whole number multiple of the section size required by the tooling, there will be no waste ends to be discarded.
The wetting of the foodstuff prior to the forming step may be performed by means of a liquid jet.
The liquid jet may be located in advance of the forming tooling so as to spray water over each severed section before it enters the tooling.
Alternatively the water jet may be directed onto the tooling so that the surface of the tooling is wet before the foodstuff is presented thereto and the foodstuff is wetted by coming into contact with the water on the surface of the tooling before the pressure is applied.
In another arrangement the jet is arranged to spray water onto the foodstuff sections when present in the tooling so that foodstuff and tooling are wetted before the tooling closes.
The wetting of the severed foodstuff sections before the forming step facilitates the shaping of the foodstuff into the desired shape.
In a particularly preferred arrangement, severed sections of frozen foodstuff each of the same size and weight, are stacked one above the other in a magazine and the conveying means is adapted to remove the section from the bottom of the stack, present it to a water jet for wetting and transfer it to the open tooling of the forming press. Additional severed frozen sections can be added to the top of the stack in the magazine to replenish those removed from the bottom of the stack, thereby enabling the process to operate continuously.
In accordance with the invention described in UK 2280869, the severed sections supplied to the top of the stack are preferably formed by severing the leading end of planks of frozen foodstuff material using a double shear tool. So as to reduce the volume of waste material, the ends of the planks are wetted and freeze welded together to form a continuous length of material for presentation to the double shear tool so that they can be cut to any size without reference to the lengths of the original planks.